An increasing number of vehicles are today equipped with one, two or more air bags, in some countries following provisions of law. The purpose of an air bag is to protect a car driver and/or a passenger, as a supplement of a car safety belt, against injuries which may otherwise appear in case of a crash against an object in front. Sensors are mounted in the car body, which sensors, in case of a strong deceleration which often precedes a collision, provides an ignition of a pyrotechnical charge which makes the air bag become inflated by said charge.
For various reasons it may occur, however, that an air bag does not become inflated during a collision, and in such cases the air bag is a latent source of accident since said air bag may later become released and inflated accidentally.
Normally, the operation of an air bag is not supposed to fail, but in very special cases this may happen, for instance in case of a side crash, if the vehicle is run into from behind, or if the vehicle rolls over. The air bag is also not supposed to become released accidentally, but this may still happen. The reason may be that the sensors for the air bag have been damaged during the accident. All known installations need a source of electric power, but even if the current to the different parts of the air bag are switched off, for instance if the poles of the electric accumulator are removed, such measurement is not quite safe. The air bag does not always automatically stop working if the current is switched off. It is said that some air bags can be active as long as up to thirty minutes after the current has been switched off.
This means that the job for the rescue personnel taking care of injured persons in the vehicle involves problems and risks. On several known occasions the rescue personnel have been injured by exploding air bags while working for instance with injured persons and persons unable to exit from the car after an accident has happened. Apart from the extremely strong explosion power that the air bag exhibits, chemical residuals are spread in the vehicle occupant compartment when the air bag is being inflated, which residuals mainly consist of sodium hydroxide powder. Such powder may give rise to corrosion injuries.